A typical disc brake rotor includes a core consisting of a hat-shaped section having a central mounting face for mounting the rotor on an associated drive member, such as a spindle or vehicle axle. The hat-shaped section also includes a generally cylindrical shoulder or hat wall extending from the periphery of the mounting face. A pair of annular friction rings or brake plates, including an inboard friction ring and outboard friction ring, can be secured to annular mounting surfaces of the core. Disc brake rotors are subjected to high mechanical and thermal stresses in practical applications, and heating of the annular friction rings may lead to stress cracks.